Connection for continuous structures



Aug. 29, 1939. R. E. TARBET 2,171,326

CONNECTION FOR CONTINUOUS STRUCTURES Filed Feb. 14, 1938 7 11 7 11 q I T 15. 9 9

Patented Aug. 29, 1939 UNITED STATES PATENT OFFICE CONNECTION FOR CONTINUOUS STRUCTURES Roy E. Tarbet, Portland, Oreg.

Application February 14, 1938, Serial No. 190,438

7 Claims. (01. 14-16) (Granted under the act of March 3, 1883, as amended April 30, 1928; 3'70 0. G. 757) This application. is made under the act of the numerals 5 and. B designate two adjacent March 3, 1888, as amended by the act of April 30, bridge girders. Two rockers I, I are pin-con- 1928, and the invention herein describe and nected to the girder 5 at 8,- 8, and one end of claimed, if patented, may be manufactured and each of the horizontal links 9, 9 are pin-con- 5 used by or for the Government of the United nected to the rockers at HI, ID. Each of the other States for governmental purposes without the ends of the links 9, 9 are pin-connected to the paymen; to me of any royalty thereon. girder 6 at H, II and a vertical. link I2 is pin- This invention relates to a device for connectconnected to the rockers 1, I at I3, l3, all sub-- ing continuous structures so that the full constantially as shown.

10 tinuity can be developed, at the same time miti- The operation of this invention is as follows: 1

gating the effect of expansion and contraction When there is a relative horizontal movement due to temperature changes or other causes, and (Figures 1 to 3) between the girder units as a is applicable for use on trusses, beams, girders, result of temperature change, or other factors, suspension bridge stiffening trusses or any other the equal travel of links 9, 9 produces equal travel type of structure where continuity is desired. 0f the points 13, I3. This does not produ y 15 An important use of this invention is found in stress in the link I2 and, therefore, no stress is relation to pontoon bridges. These bridges conset up in the entire system, thus providing perfect sist of individual floating pontoons connected end fr m of m vem n horizontally H w v to end. If these pontoons are joined together when a moment exists at the joint due to the apin such a manner that the connections will-not pl oation of a vertical load, the stress in links 9, 20 take a moment stress, heavy concentrations of 9 becomes equal but of .opposite algebraic sign, load on the ends of adjacent pontoons will pro- Producing equal a pp te de cies to move duce objectionable break in the grade line and points Which are e d by link he revertical movement. One of the objects of this Sll t o this effect is that no movement occurs.

invention is to obviate such an unsatisfactory Under certain conditionsatemperature c a 25 condition by making the entire bridge act as a at the top of a girder y be different from a continuous beam, thereby eliminating break in at the bottom. For examp Such a Condition grade and reducing vertical movement to a miniy arise in the ease of a pontoon bridge Where the temperature of the portion under water would Continuous structures, such as trusses and be d fierent om that out of the water. This 30 girders, usually consist of a series of continuous d erence would produce a very s a angular span units, At th nds of th it it was change in the end of each pontoon which would heretofore necessary to break the continuity to be equivalent to the application o a ment beprovide means for taking care of the effect of tween t pontoons- W s f e ence is expansion and contraction. By utilizing this great enough to require Compensation, one o the 35 invention, the efiect of expansion and contraction pin Connections I ay be p ov ded is provided for in addition to making any plural- With a Slight amount of p xa p e, t

ity of spans fully continuous. may be made slightly slotted. The shear key The following description, considered together Prevents y Vertical movement of the mem- 40 with the accompanying drawing, will more fully her 5 relative to the member 6. 40 disclose this invention, its constructions and op- Since each unit is free to act independently erations of parts, and further objects and ady movement other than moment, flexivantages thereof will be apparent. bility in a horizontal plane, perpendicular to the In th drawing; principal plane of bending is retained. Thus,

Figure 1 is a front elevational view of this indeflection caused by Wind, fluid p e, or t er 45 ventio-n. in one of its forms shown in a normal forces Settmg up Small angular changes between position as applied t adjacent, ends of two units produce no stress when this invention is ordinary bridge girders. p y

Figure 2 is the same view as Figure 1 showin Should it be desired to limit the amount of the invention in a closed position. movement between each connected unit, ties, 50

Figure 3 is the same View as Figure 1 showing bumpers, or other suitable means may be emthe invention in an open position. ployed.

Figure 4 is' a side View of Figure 1. By the use of this invention, all members ex- Referring with more particularity to the drawcept the rockers and pins carry direct stress only. ing in which like numerals designate like parts, This leads to economy in design. 55

While for the purpose of illustration the link connections have been shown in single shear, it is to be understood that providing said links with double shear connections is within the scope and spirit of this invention.

Having thus described my invention, I claim:

1. A connection for continuous structural units comprising two congruent rockers in spaced relation, each rocker having two lever arms, said rockers being correspondingly disposed and pin connected to one of said units, a rigid link having its ends pin connected to corresponding lever arms of said rockers, and parallel links each connecting the other lever arm of one rocker to the adjacent structural unit.

2. A connection for adjacent structural units comprising two congruent rockers corresponding- 1y disposed and pin connected near the top and bottom respectively at the end of one of said units, each of said rockers having two lever arms, a rigid link connecting corresponding lever arms of said rockers with each other, and parallel links each connecting the other lever arm of one rocker to the end of the other structural unit.

3. A connection for continuous structural units comprising two congruent double lever rockers in lateral alignment pin connected to one of said units, a rigid link connecting corresponding lever arms of said rockers, parallel links each connecting the other lever arm of one of said rockers to the adjacent structural unit.

4. In combination with continuous structural units congruent bell cranks correspondingly disposed and pivoted to one of said units, means linking congruent lever arms of said bell cranks, and parallel links each connecting the other lever arm of one of said bell cranks to the adjacent structural unit, the levers of said bell cranks being so arranged that rotation thereof is normally in the same direction.

5. In combination with continuous structural units congruent double lever bell cranks correspondingly disposed, pivoted to one of said units in vertical, alignment, a rigid link connecting the parallel lever arms of said bell cranks, and parallel links each connecting the other lever arm of one of said bell cranks to the adjacent structural unit.

6. A connection for adjacent structural units comprising a plurality of congruent bi-lever bell cranks correspondingly disposed and pivoted to one of said units, a rigid link connecting corresponding lever arms to each of said bell cranks for normal rotation in the same direction, and a plurality of parallel links, each of said links connecting the other lever arm of one bell crank to the adjacent structural unit,

'7. A connection for adjacent structural units comprising a plurality of congruent bi-lever bell cranks correspondingly disposed and pivoted to one of said units, a rigid link connecting corresponding lever arms to each of said bell cranks for normal rotation in the same direction, and a plurality of parallel links each of said links connecting the other lever arm of one bell crank to the adjacent structural unit, one of said connections having a slight amount of lost motion.

ROY E. TARBET. 

